I am afraid the answer is simple, she is not mentally tough enough ( she needs a psyhcologist ), she could be the next coming of Maria Butyrskaya
we may have to wait maybe a max 10 years if she is still competing before she can skate 2 clean programs ( The Maria Butyrskaya 2.0 )

Ten years? So Sotnikova will be 26 before we see her skate another clean competition?

She said after the SP that she didn't know what happened with her 3F--that makes me think that her problem is technical, not mental. No "I was nervous" or "I got caught up in the moment." I could be wrong, but the fact that it's the 3F and none of the other jumps (until the FS, where she was clearly insecure) suggests a tiny detail that somewhere, somehow got overlooked.

Also, I refrain from making huge umbrella statements like "she is not mentally tough enough" over the results of one competition. I like to keep in mind that an entire thread was dedicated to questioning Gracie Gold's ability to handle pressure after Skate Canada, and she made all of her career-harbingers look foolish after CoR.

But this is not one competition. You can't find a competition where she has done great from 2011 junior worlds. She won Russian nationals and Medaled at everything until COR but every competition major trouble. That includes 2012 Russian nationals after the halfway point and she was beaten by lipnitskaia in the fs. But people have a great excuse: she is growing and that just means she can single flips and fall on flips and mess up double Axels and even is a reason to zayak and do to many combos!